Definition - What does Fading mean?
Fading is the loss of sheen and luster from a painted or processed metallic surface due to exposure to external factors, surface aging or manual manipulation. Fading is an indication that renewed surface treatment is required to prevent erosion and maintain surface corrosion resistance.
Corrosionpedia explains Fading
Fading is present in coats and liners used to safeguard metallic surfaces from the impacts of corrosion. Such liners and coats should always be reapplied once fading is noticed to prevent the onset of corrosion.